1. Field of the Invention
The present invention relates to a sheet-convey device configured to recognize a width of a sheet to be conveyed, and relates to an image reading device which is equipped with the sheet-convey device.
2. Description of the Related Art
A conventional image reading device is provided with a sheet-convey device. The sheet-convey device conveys a document sheet placed on a sheet holder along a sheet-convey path and discharges the document sheet onto a sheet-discharge tray. In the image reading device, an image of the document sheet passing through the sheet-convey path is read, at a specific position of the sheet-convey path, by a line sensor in a process in which the document sheet is conveyed.
Patent Document 1 (Japanese Patent Application Publication No. 2006-115428) discloses an image reading device provided with a sheet sensor and a sheet-width sensor on a sheet-convey path. The sheet sensor is for sensing the document sheet being conveyed through the sheet-convey path. The sheet sensor is provided at a position at which document sheets of all sizes which are conveyed along the sheet-convey path can be sensed. The sheet-width sensor is for sensing an edge portion of the document sheet in a direction perpendicular to a direction in which the document sheet is conveyed. On the basis of a result of the sensing of the sheet-width sensor, there is judged whether the document sheet to be conveyed along the sheet-convey path is a document sheet of a relatively large size (e.g., A3 size and B4 size) or a document sheet of a relatively small size (e.g., A4 size and B5 size). Since the sheet-width sensor is provided on the sheet-convey path, even where a plurality of the document sheets of different sizes are stacked on the sheet tray, a width of the document sheet can be recognized when the document sheet is supplied or introduced into the sheet-convey path.
Patent Document 2 (Japanese Patent Application Publication No. 62-93168) discloses an image reading device in which six sensors for sensing a document sheet are provided on a sheet tray. These sensors are arranged in a row in a direction perpendicular to a direction in which the document sheet is conveyed. In this image reading device, on the basis of a result of the sensings of the respective sensors, a width of the document sheet placed on the sheet tray is recognized.
Further, on a sheet tray of the conventional image reading device, there are provided a pair of side guides. The side guides are respectively brought into contact with side edges of the document sheet placed on the sheet tray. The side guides are slidable in a widthwise direction of the sheet tray (the above-described direction perpendicular to the direction in which the document sheet is conveyed). These side guides are constructed such that when one of the side guides is slid in a certain direction in the widthwise direction, the other of the side guides is cooperated to be slid in a direction opposite to the certain direction. When the side guides are slid in a state in which the document sheet is placed on the sheet tray, the side guides are respectively brought into contact with both of the side edges of the document sheet, whereby the document sheet is positioned. As a result, regardless of a width of the document sheet placed on the sheet tray, a center of the document sheet in the widthwise direction is positioned at a prescribed position (e.g., a center of the sheet tray in the widthwise direction).